It will be recalled that the "saddle stem" is the tubular member whose lower part is inserted in the saddle tube of the frame, with the possibility of vertical adjustment, whereas the "saddle frame" is the metal frame, composed essentially of two substantially parallel longitudinal members, by means of which the saddle proper is fixed.
Various saddle supports of this type, facilitating an adjustment of the longitudinal position and inclination, as well as locking in the chosen position, are known. Certain of these supports comprise a single member or two side plates mounted to pivot about a transverse shaft on the saddle stem. The part or side plates in question serve as guides for the sliding movement of the saddle frame and thus simultaneously ensure adjustment of the inclination and longitudinal position, the locking of the saddle frame being ensured by means comprising screws. Another well-known saddle support comprises two cross bars which both bear on the two longitudinal members of the saddle frame. These two cross bars are connected to the head of the saddle stem by means of screws, which make it possible to adjust the distance of each cross bar from the head of the saddle stem in order to adjust the inclination of the saddle, the tightening of these screws thus ensuring locking of the saddle in the desired longitudinal position. Finally, it is also possible to mention a further saddle support, in which the head of the saddle stem has a concave upper side, on which rests a cradle having an adjustable inclination, with two channels receiving the longitudinal members of the saddle frame. A small plate, pressed against these longitudinal members by the tightening of a screw passing through the aforesaid cradle, ensures the immobilization of the saddle in the desired longitudinal position as well as the locking of the cradle in the desired inclination.
All these devices, including the last-mentioned, which comprises only one adjusting and locking screw, are very complicated mechanically, in the sense that they comprise numerous moving parts and their adjusting and locking means are frequently only accessible with difficulty.